1. Technical Field
This invention relates to rail car doors that are of the type that are pivoted into and out of closure opening and slide transversely of the rail car wall thereafter.
2. Description of Prior Art
Prior art devices of this type have been directed for use on railway plug doors that use pivotal crank rod assemblies that support the door and crank activation rods that extend to a central door operation handle assembly. Such operational mechanisms have a selector gear with an interconnected activation drive pinion gear. Activation crank rods extend from the selector gear for opening and closing the door. The pinion gear has an operational handle for manual input thereto. Prior art anti-spin drives take the place of a pinion gear and have a ratchet gear engaged by directional pawl. Such devices prevent rapid spinning of the operational handle in one direction if the door is accidentally moved by cargo or loaders. The anti-spin devices of this type can be seen in U.S. Pat. Nos. 3,557,731, 3,660,938 and 4,920,894.
In U.S. Pat. No. 3,555,731 a ratchet lock is disclosed that replaces a standard pinion gear for engagement of a door operational gear. During rotation of the device""s drive shaft to open the door from the door opening, the pinion gear will move in a direction to engage and clamp a ratchet wheel between it and a flange fixed to the shaft with an engagement pawl on the ratchet wheel so as to allow the clamped ratchet wheel to rotate in direction with the pinion gear to open the door and prevent rotation of the wheel in opposite direction to close the door.
In U.S. Pat. No. 3,660,938 a brake type drive mechanism is disclosed for plug type rail car doors having a pinion gear on a rotatable input shaft that when the drive mechanism connected to the door crank moves at a rate faster than that of the pinion gear and attached handle the pinion gear will move longitudinally on the drive shaft engaging a ratchet wheel that prevents further movement.
In U.S. Pat. No. 4,920,894 a modular anti-spin unit for railway car doors is disclosed which is secured to the existing handle of the actuation shaft that prevents rapid shaft rotation in one direction by frictional engagement with a ratchet gear.
The present invention provides for method of retrofitting a railway car door with a dual action multi-directional safety mechanism by replacing a standard pinion gear or one-way anti-spin mechanism. The safety mechanism includes a pair of rotatable pinion gears that have extended engagement travel restriction lugs extending therefrom. The pinion gears are threadably positioned on a handle drive shaft with a ratchet gear assembly being rotatably positioned over the respective lugs between frictional rings and held in place by respective apertured pressure plates. Upon unintentional rapid rotation of the drive handle shaft, the friction ring wedgeably engages the ratchet gear stopping directional rotation of the pinion gear interconnected therewith.
A method for replacing an existing rail car door handle activation assembly including multiple steps of removing and modifying existing components and adding selected fittings required to adapt the dual action anti-spin, anti-drift safety mechanism to an existing rail car door assemblies.